U.S. patent number 8,944,766 [Application Number 13/255,706] was granted by the patent office on 2015-02-03 for rotor lock for a wind turbine.
This patent grant is currently assigned to Vestas Wind Systems A/S. The grantee listed for this patent is Erik Markussen, Flemming Selmer Nielsen. Invention is credited to Erik Markussen, Flemming Selmer Nielsen.
United States Patent |
8,944,766 |
Nielsen , et al. |
February 3, 2015 |
Rotor lock for a wind turbine
Abstract
A locking arrangement for locking a hub (1) of a wind turbine
against rotational movement is disclosed. The locking arrangement
comprises at least one first locking part (6) and at least one
second locking part (8). The first locking part(s) (6) is/are
movable along a substantially radial direction relative to the
rotational axis of the hub (1), between a locking position and a
release position. Each second locking part (8) is adapted to retain
a first locking part (6) when the first locking part (6) is in the
locking position. The first locking part(s) (6) and the second
locking part(s) (8) are arranged with one of them on the hub (1)
and the other one on the base frame (5). Thereby, a first locking
part (6) and a second locking part (8) prevent rotational movement
of the hub (1) relative to the base frame (5) when the first
locking part (6) is in the locking position, and allow such
movement when the first locking part (6) is in the release
position.
Inventors: |
Nielsen; Flemming Selmer
(Hammel, DK), Markussen; Erik (Videbaek,
DK) |
Applicant: |
Name |
City |
State |
Country |
Type |
Nielsen; Flemming Selmer
Markussen; Erik |
Hammel
Videbaek |
N/A
N/A |
DK
DK |
|
|
Assignee: |
Vestas Wind Systems A/S (Aarhus
N., DK)
|
Family
ID: |
42728863 |
Appl.
No.: |
13/255,706 |
Filed: |
March 8, 2010 |
PCT
Filed: |
March 08, 2010 |
PCT No.: |
PCT/EP2010/052881 |
371(c)(1),(2),(4) Date: |
September 29, 2011 |
PCT
Pub. No.: |
WO2010/102967 |
PCT
Pub. Date: |
September 16, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20120070304 A1 |
Mar 22, 2012 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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61159997 |
Mar 13, 2009 |
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Foreign Application Priority Data
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Mar 13, 2009 [DK] |
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2009 00358 |
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Current U.S.
Class: |
416/169R;
416/244R |
Current CPC
Class: |
F03D
80/50 (20160501); F03D 80/00 (20160501); F05B
2260/30 (20130101); F05B 2260/31 (20200801); Y02E
10/72 (20130101) |
Current International
Class: |
F03D
11/00 (20060101) |
Field of
Search: |
;416/169R,244R,248 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10 2004 028 746 |
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Dec 2005 |
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DE |
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10 2007 058 746 |
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Dec 2008 |
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DE |
|
1 167 755 |
|
Jan 2002 |
|
EP |
|
1 291 521 |
|
Mar 2003 |
|
EP |
|
1 617 075 |
|
Jan 2006 |
|
EP |
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1 748 182 |
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Jan 2007 |
|
EP |
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1 772 624 |
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Apr 2007 |
|
EP |
|
2148090 |
|
Jan 2010 |
|
EP |
|
10 0821704 |
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Apr 2008 |
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KR |
|
2008/059088 |
|
May 2008 |
|
WO |
|
Other References
Paolo Burattini; International Preliminary Report on Patentability
issued in priority international patent application No.
PCT/EP2010/052881; Sep. 13, 2011; 5 pages; European Patent Office.
cited by applicant .
Jens Skou; 1st Technical Examination and Search Report issued in
priority Denmark Application No. PA 2009 00358; Oct. 27, 2009; 6
pages; Denmark Patent and Trademark Office. cited by applicant
.
Paolo Burattini; International Search Report issued in priority
International Application No. PCT/EP2010/052881; Apr. 26, 2011; 5
pages; European Patent Office. cited by applicant .
European Patent Office, Office Action issued in corresponding
European Application No. 10706674.8, dated Aug. 2, 2014, 4 pages.
cited by applicant.
|
Primary Examiner: McDowell; Liam
Attorney, Agent or Firm: Wood, Herron & Evans, LLP
Claims
The invention claimed is:
1. A wind turbine, comprising: a tower; a nacelle supported by the
tower and including a base frame; a rotor including a hub adapted
to perform rotational movements about a rotational axis and a
plurality of turbine blades coupled to the hub; and a locking
arrangement, comprising: a first locking part movable along a
substantially radial direction relative to the rotational axis of
the hub between a locking position and a release position; and a
second locking part adapted to retain the first locking part when
the first locking part is in the locking position, wherein one of
the first locking part and the second locking part is formed in or
mounted on the hub, and the other of the first locking part and the
second locking part is formed in or mounted on the base frame, the
first locking part and the second locking part thereby preventing
rotational movement of the hub relative to the base frame when the
first locking part is in the locking position, and allowing such
movement when the first locking part is in the release position,
wherein the first locking part is configured to prevent tilt and/or
yaw movements of the hub when the first locking part is in the
locking position, and wherein the locking arrangement further
comprises a fixing device for preventing the movement of the first
locking part away from the locking position, the fixing device
being incapable of actively moving the first locking part relative
to the second locking part, and the fixing device being
positionable between and engageable with the first locking part and
the base frame to block movement of the first locking part away
from the locking position.
2. The wind turbine of claim 1, wherein the first locking part
includes a movable pin with a tapered outermost portion, and the
second locking part includes a tapered opening that snugly receives
the tapered outermost portion of the movable pin in the locking
position.
3. The wind turbine of claim 1, wherein the locking arrangement
includes a mounting plate coupled to the base frame so as to define
a space between the mounting plate and the base frame, the space
enabling visual confirmation as to whether the first locking part
is in the locking position or the release position.
4. The wind turbine of claim 1, wherein the second locking part is
formed in a flange part of the hub or the base frame.
5. The wind turbine of claim 4, wherein the flange part forms an
integral part of the hub or the base frame.
6. The wind turbine of claim 1, wherein the locking arrangement
comprises at least two first locking parts and at least two second
locking parts.
7. The wind turbine of claim 6, wherein the at least two first
locking parts are arranged substantially opposite to each
other.
8. The wind turbine of claim 6, wherein the locking arrangement
comprises at least 12 second locking parts, the second locking
parts being arranged with substantially equal angular distance
between neighboring second locking parts.
9. The wind turbine of claim 1, wherein the locking arrangement
further comprises a sensor device configured to detect whether or
not the first locking part and the second locking part are arranged
at corresponding positions.
10. The wind turbine of claim 1, wherein a part of the base frame
substantially circumscribes a part of the hub.
11. A wind turbine, comprising: a tower; a nacelle supported by the
tower and including a base frame; a rotor including a hub adapted
to perform rotational movements about a rotational axis and a
plurality of turbine blades coupled to the hub; and a locking
arrangement, comprising: a first locking part movable along a
substantially radial direction relative to the rotational axis of
the hub between a locking position and a release position; and a
second locking part adapted to retain the first locking part when
the first locking part is in the locking position, wherein one of
the first locking part and the second locking part is formed in or
mounted on the hub, and the other of the first locking part and the
second locking part is formed in or mounted on the base frame, the
first locking part and the second locking part thereby preventing
rotational movement of the hub relative to the base frame when the
first locking part is in the locking position, and allowing such
movement when the first locking part is in the release position,
and wherein the first locking part is configured to prevent tilt
and/or yaw movements of the hub when the first locking part is in
the locking position, wherein the locking arrangement includes a
mounting plate coupled to the base frame so as to define a space
between the mounting plate and the base frame, the space enabling
visual confirmation as to whether the first locking part is in the
locking position or the release position, and the locking
arrangement further comprises a fixing device configured as a block
positionable in the space between the mounting plate and the base
frame for preventing the movement of the first locking part away
from the locking position.
12. The wind turbine of claim 11, wherein the first locking part
includes a movable pin with a tapered outermost portion, and the
second locking part includes a tapered opening that snugly receives
the tapered outermost portion of the movable pin in the locking
position.
13. The wind turbine of claim 11, wherein the second locking part
is formed in a flange part of the hub or the base frame.
14. The wind turbine of claim 13, wherein the flange part forms an
integral part of the hub or the base frame.
15. The wind turbine of claim 11, wherein the locking arrangement
comprises at least two first locking parts and at least two second
locking parts.
16. The wind turbine of claim 15, wherein the at least two first
locking parts are arranged substantially opposite to each
other.
17. The wind turbine of claim 15, wherein the locking arrangement
comprises at least 12 second locking parts, the second locking
parts being arranged with substantially equal angular distance
between neighboring second locking parts.
18. The wind turbine of claim 11, wherein the locking arrangement
further comprises a sensor device configured to detect whether or
not the first locking part and the second locking part are arranged
at corresponding positions.
19. The wind turbine of claim 11, wherein a part of the base frame
substantially circumscribes a part of the hub.
Description
FIELD OF THE INVENTION
The present invention relates to a locking arrangement for locking
a hub of a wind turbine against rotational movements relative to a
base frame of the nacelle of the wind turbine. Such a locking
arrangement is, e.g., required for safety purposes in order to
prevent the hub from rotating during maintenance of the wind
turbine.
BACKGROUND OF THE INVENTION
Various components of a wind turbine, including components arranged
in or near the nacelle, such as drive train, main shaft, generator,
main bearing or hub, sometimes require maintenance, repair or
replacement. It is therefore necessary to allow maintenance
personnel to gain access to these parts in order to allow them to
perform the required maintenance, repair or replacement. This will
sometimes include gaining access to an interior part of the hub.
For safety reasons the rotor must be prevented from performing
rotational movements during such maintenance operations.
A number of locking arrangements have previously been suggested in
order to provide a suitable locking of the rotor against rotational
movements. WO 2008/059088 A1 discloses an adjustable, self-aligning
rotor locking device for an aerogenerator, comprising a rotor, a
nacelle structure housing power generating means coupled to the hub
of the rotor, braking means and means for controlling the
rotational position of the power train. The nacelle structure and
the hub of the rotor are arranged so as to prevent the rotor hub
from rotating during certain maintenance and assembly operations.
The arrangement includes at least one mobile pin in the nacelle,
actuation means for pushing/pulling the pin axially in relation to
at least one corresponding hole in the hub.
EP 1 291 521 A1 discloses a wind turbine comprising a nacelle on a
tower. The wind turbine is provided with a rotor lock device for
locking a rotor disk and fixation means for fixing the rotor disk
to the nacelle. The rotor lock device comprises an axially movable
pin arranged on the nacelle structure and corresponding apertures
formed in the rotor disk.
Thus, WO 2008/059088 A1 and EP 1 291 521 A1 both disclose rotor
locking arrangements in which a movable member is moved along a
substantially axial direction between a position in which the rotor
is locked against rotational movements and a position in which the
rotor is allowed to perform rotational movements. A disadvantage of
such an arrangement is that it is not possible to use the locking
mechanism directly for absorbing tilt or yaw loads, e.g. in the
case that the support for the main shaft, or the main shaft itself,
needs to be removed during the maintenance operation. Another
disadvantage is that it is difficult and relatively expensive to
manufacture the hub in a manner which allows the axial movement of
the locking parts.
EP 1 617 075 A1 discloses a method and an apparatus for changing a
transmission of a wind power installation. The rotor shaft is
supported on the machine frame during the transmission change
operation by means of a support at the transmission side so that
the rotor is permitted to remain on the rotor shaft during the
transmission change. The support is a yoke which is mounted between
the rotor shaft and the machine frame immediately prior to the
transmission change and is removed again immediately after the
transmission change. In the case that the drive train is suspended
in the nacelle by means of a so-called three point suspension, the
yoke supports the main shaft when the gear is removed during a
replacement operation, thereby removing part of the normal support
of the drive train. The yoke may further prevent the main shaft
from performing rotational movements, due to friction between the
yoke and the main shaft. However, this rotational locking is too
unreliable to be used as a safety measure during maintenance
operations.
DESCRIPTION OF THE INVENTION
It is an object of the invention to provide a locking arrangement
for a hub of a wind turbine which is capable of preventing
rotational movements of the hub as well as tilt and/or yaw
movements of the hub.
It is a further object of the invention to provide a locking
arrangement for a hub of a wind turbine which is capable of
preventing rotational movements of the hub during removal or
replacement of the main shaft.
It is an even further object of the invention to provide a locking
arrangement for a hub of a wind turbine in which rotational locking
of the hub is more reliable than the locking provided by prior art
locking arrangements.
It is an even further object of the invention to provide a locking
arrangement for a hub of a wind turbine, wherein the locking
arrangement is easier and more cost effective to manufacture than
prior art locking arrangements.
According to the invention there is provided a locking arrangement
for a hub of a wind turbine, said hub being adapted to perform
rotational movements about a rotational axis, said wind turbine
comprising a nacelle having a base frame, the locking arrangement
comprising: at least one first locking part, the first locking
part(s) being movable along a substantially radial direction
relative to the rotational axis of the hub, between a locking
position and a release position, and at least one second locking
part, each second locking part being adapted to retain a first
locking part when the first locking part is in the locking
position, wherein one of the first locking part(s) and the second
locking part(s) is/are formed in or mounted on the hub, and the
other of the first locking part(s) and the second locking part(s)
is/are formed in or mounted on the base frame, a first locking part
and a second locking part thereby preventing rotational movement of
the hub relative to the base frame when the first locking part is
in the locking position, and allowing such movement when the first
locking part is in the release position.
Modern wind turbines normally comprise a tower construction
carrying a nacelle. The nacelle carries a rotor with a hub having a
set of turbine blades attached thereto, and it accommodates various
components used for converting energy of the wind into electrical
energy, e.g. a generator and a drive train. The nacelle is mounted
on top of the tower construction in such a manner that it is
capable of performing rotating movements about a substantially
vertical axis, thereby allowing the wind turbine to direct the
turbine blades in the direction of the wind. The nacelle normally
has a base frame, forming a structural part of the nacelle, and a
cover defining a closed interior part of the nacelle which is used
for accommodating the components mentioned above.
During operation wind interacts with the turbine blades and causes
rotation of the rotor about a rotational axis which is arranged in
a substantially horizontal, possibly slightly inclined, plane. This
rotation is transformed into electrical energy which is
subsequently supplied to a grid. Thus, during operational
conditions the rotor must be allowed to rotate.
However, in the case that it is necessary to perform maintenance,
repair or replacement on one or more of the components accommodated
in the nacelle, or on the rotor, the presence of maintenance
personnel in the nacelle, and possibly in the vicinity of or even
in an interior part of the rotor, is required. When maintenance
personnel are present in these regions of the wind turbine,
rotation of the rotor can lead to dangerous and possibly fatal
situations. It is therefore a requirement that the rotor is
prevented from performing rotating movements under these
circumstances. The locking arrangement of the invention can be used
for locking the hub, and thereby the rotor, against rotating
movements.
The locking arrangement comprises at least one first locking part
and at least one second locking part. Each of the first locking
part(s) is movable along a substantially radial direction. In the
present context the term `substantially radial direction` should be
interpreted to mean a direction which is substantially
perpendicular to a direction defined by the rotational axis about
which the hub rotates during normal operation of the wind turbine,
and which intersects the rotational axis. Radial movements of the
first locking part cause the first locking part to be moved between
a locking position and a release position. When the first locking
part is in the locking position, the locking arrangement locks the
hub against rotational movements, and when the first locking part
is in the release position, the locking arrangement allows the hub
to perform rotational movements, i.e. the wind turbine is allowed
to operate in a normal manner. This will be explained further
below.
The second locking part is adapted to retain a first locking part
when the first locking part is in the locking position. Thus,
interaction between a first locking part and a second locking part
causes these two locking parts to be locked together, thereby
causing the parts of the wind turbine which carries the two locking
parts to be locked together.
One of the first locking part(s) and the second locking part(s)
is/are formed in or mounted on the hub, and the other of the first
locking part(s) and the second locking part(s) is/are formed in or
mounted on the base frame. Thus, in one embodiment, the first
locking part(s) is/are formed in or mounted on the hub, while the
second locking part(s) is/are formed in or mounted on the base
frame. Alternatively, the first locking part(s) may be formed in or
mounted on the base frame, while the second locking part(s) is/are
formed in or mounted on the hub. In any event, when a first locking
part is moved to the locking position, thereby being retained by a
second locking part, the hub and the base frame are locked to each
other by means of the first locking part and the second locking
part. Thereby the hub is not allowed to perform rotational
movements relative to the base frame when the first locking part(s)
is/are in the locking position. However, when each of the first
locking part(s) is in the release position, the hub and the base
frame are not locked together, and the hub is therefore allowed to
perform rotational movements relative to the base frame, i.e. the
wind turbine is allowed to operate in a normal manner.
Thus, the locking arrangement may advantageously be operated in the
following manner. During normal operation each of the first locking
part(s) is in the release position. When it is desired to perform
maintenance, repair or replacement requiring the presence of
maintenance personnel in the nacelle, some or all of the first
locking part(s) is/are moved to the locking position, thereby
preventing the hub from performing rotational movements. When the
maintenance, repair or replacement has been completed, the first
locking part(s) is/are moved back to the release position, and the
wind turbine is once again allowed to operate in a normal
manner.
It should be noted that the first/second locking part(s) may be
formed directly in or form an integral part of the hub/base frame.
Alternatively, the first and/or the second locking part(s) may be
(a) separate part(s) mounted on the hub/base frame.
It is an advantage that the locking arrangement directly locks the
hub and the base frame because the locking arrangement is thereby
completely independent of the drive train. This makes it possible
to remove or replace all components of the drive train, including a
main shaft, while the rotor is efficiently prevented from
performing rotating movements.
It is an advantage that the movement causing the hub and the base
frame to be locked to each other is performed along a substantially
radial direction, rather than along a substantially axial
direction, because the radial movement introduces less play in the
connection between the locking parts. Furthermore it is easier and
more cost effective to manufacture the hub and the base frame with
locking parts which can engage along a substantially radial
direction than with locking parts which can engage along a
substantially axial direction. Furthermore, the point of engagement
between a first locking part and a second locking part can be
located at a larger distance from the rotational axis of the hub,
thereby resulting in a larger lever arm and consequently a larger
torque of the locking movement. Accordingly, an improved locking
between the hub and the base frame is obtained. Finally, the radial
locking movement allows the locking arrangement to directly absorb
tilt or yaw loads of the hub without requiring additional locking
means or support means, such as the support means disclosed in EP 1
617 075 A1.
Each of the first locking part(s) may comprise a movable pin, and
each of the second locking part(s) may comprise an opening adapted
to receive a pin of a first locking part. According to this
embodiment, the pin is moved in a direction towards an opening when
the first locking part is moved from the release position to the
locking position, thereby causing the pin to be received and
retained by means of the opening, and the pin is moved in a reverse
direction when the first locking part is moved from the locking
position to the release position.
The pin(s) and the opening(s) may advantageously have substantially
circular cross sections of substantially identical diameter, since
it is very easy to produce pins and openings having a circular
cross section. However, the cross sections of the pin(s) and the
opening(s) may have any desired shape, including square,
rectangular, triangular, hexagonal, oval, etc., as long as the
cross sectional shape of the pin(s) and the cross sectional shape
of the opening(s) match each other, thereby allowing a pin to be
received in an opening.
The pin(s) and the opening(s) may have matching tapered shapes in
such a manner that the pin(s) is/are tapered in a direction towards
the opening(s). This makes it possible to allow a pin to be
received in an opening, even if the pin and the opening are not
positioned exactly at corresponding positions. However, a matching
tapered shape of the opening ensures a firm engagement between the
pin and the opening once the first locking part has been moved to
the locking position.
The movements of the first locking part(s) may be performed by
means of a mechanical pump, by means of a hydraulic actuator, by
means of an electrical actuator, in a manual manner, e.g. using a
threaded spindle, or in any other suitable manner. Movement of the
first locking part(s) may be initiated locally, e.g. by maintenance
personnel present on the site of the wind turbine. Alternatively or
additionally, it may be possible to initiate movement of the first
locking part(s) from a remote position, e.g. by sending a signal to
one or more actuators used for performing the movements. In this
case the hub may already be locked when the maintenance personnel
arrives at the site. This may be an advantage in the case that the
wind turbine is arranged at an offshore location, since the
maintenance personnel may, in this case, arrive by helicopter, and
it may be an advantage that the hub, carrying the turbine blades,
is not rotating when the helicopter arrives. Furthermore, one
activation mechanism may be used for performing movements of two or
more first locking parts, and possibly all the first locking parts
of the locking arrangement.
The second locking part(s) may be formed in a flange part of the
hub or the base frame. The flange part may form an integral part of
the hub or the base frame. In this case the flange part may, e.g.,
be cast directly together with the hub or the base frame, or it may
be machined directly into the hub or the base frame. Alternatively,
the flange part may be a separate part which is subsequently
mounted on the hub or the base frame, e.g. by welding or by means
of bolts or screws.
As an alternative to the flange part, the second locking part(s)
may be formed directly into another part of the hub or the base
frame.
The locking arrangement may comprise at least two first locking
parts and at least two second locking parts. According to this
embodiment, the locking arrangement is capable of locking the hub
and the base frame together in at least two positions. The at least
two first locking parts may be arranged substantially opposite to
each other, i.e. angularly spaced with 180.degree. between the two
first locking parts. It should be noted that this does not rule out
that additional first locking parts are arranged between the two
oppositely arranged first locking parts.
It should be noted that the number of first locking parts and the
number of second locking parts are not necessarily identical. For
instance, the locking arrangement may comprise two first locking
parts and four second locking parts. This could potentially allow
the hub and the base frame to be locked to each other at four
different mutual positions.
The locking arrangement may comprise at least 12 second locking
parts, the second locking parts being arranged with substantially
equal angular distance between neighbouring second locking parts.
In the case that the locking arrangement comprises exactly 12
second locking parts, the second locking parts will be arranged
angularly spaced with 30.degree. between neighbouring second
locking parts. In the case that the wind turbine comprises three
turbine blades, this would allow the hub to be locked to the base
frame at a position where a turbine blade is directed downwards, at
a position where a turbine blade is directed upwards, a position
where a turbine blade is directed horizontally to the right and a
position where a turbine blade is directed horizontally to the
left.
The locking arrangement may further comprise a sensor device
arranged to detect whether or not a first locking part and a second
locking part are arranged at corresponding positions. When a first
locking part and a second locking part are arranged at
corresponding positions, the first locking part can be moved to the
locking position and be received and retained by the second locking
part. On the other hand, when a first locking part is not arranged
at a position corresponding to a position of a second locking part,
it is not possible to move the first locking part to the locking
position and be received and retained by a second locking part.
Thus, according to this embodiment, the sensor device can detect
whether or not the relative position of the hub and the base frame
allows the locking arrangement to be activated to lock the hub
against rotational movements relative to the base frame. This
detection can be used for carefully moving the hub to a position
where it is possible to lock it, and subsequently initiate the
locking.
The locking arrangement may further be adapted to prevent tilt
and/or yaw movements of the hub when at least one first locking
part is in the locking position. As mentioned above, the radial
movement of the first locking part(s) between the locking position
and the release position in itself makes this possible. This allows
all components of the drive train, including the main shaft and
including the gear in case of a three-point suspension of the drive
train, to be removed without requiring additional support
arrangements, and without having to remove the hub.
The locking arrangement may further comprise a yoke part arranged
to cooperate with the first locking part(s) and the second locking
part(s) in order to prevent tilt and/or yaw movements of the hub.
The yoke part may be adapted to be detachably mounted on the base
frame or the hub. In this case the yoke part may be mounted on the
base frame only when the maintenance operation requires that the
gear or the main shaft is removed. The yoke part can be removed
again when the maintenance operation has been completed. As an
alternative, the yoke part may be permanently mounted on the base
frame, or it may form an integral part of the base frame.
The locking arrangement may further comprise a safety system, said
safety system preventing access to an interior part of the hub when
the first locking part(s) is/are in the release position. The
safety system may, e.g., be coupled to a locking system of a hatch
or a door arranged across an opening creating access to the hub. In
this case the safety system may prevent the locking system from
being unlocked if the first locking part(s) is/are in the release
position, i.e. if the hub is allowed to rotate relative to the base
frame. Thereby it is ensured that maintenance personnel can only
gain access to the interior part of the hub if the hub is securely
locked to the base frame.
A part of the base frame may substantially circumscribe a part of
the hub. According to this embodiment, first and second locking
parts can be arranged along the entire perimeter circumscribing the
rotational axis of the hub, and thereby it is possible to
distribute the locking forces between the hub and the base frame in
an even manner. Furthermore, when the base frame substantially
circumscribes a part of the hub, the base frame helps in absorbing
the tilt and yaw movements of the hub as described above.
As an alternative, the base frame may only circumscribe part of the
hub.
The locking arrangement may further comprise means for fixating the
first locking part(s) in the locking position. The fixating means
may be of a pure mechanical kind, such as a block, a pin, a spindle
inserted into each first locking part in such a manner that the
first locking part(s) is/are prevented from moving to the release
position. The fixating means provides an additional safety measure
during maintenance, repair or replacement of components in the
vicinity or in an interior part of the hub.
As described above, when it is desired to perform this kind of
maintenance operation, the maintenance personnel initially ensures
that the first locking part(s) is/are moved to the locking
position, thereby preventing rotation of the hub relative to the
base frame. When this has been ensured, the maintenance operation
is initiated, and this possibly includes that maintenance personnel
enters an interior part of the hub. There is, however, a risk that
the first locking part(s) is/are accidentally moved to the release
position before the maintenance operation has been completed,
potentially leading to dangerous situations. This risk may, e.g.,
be present when it is possible to activate movements of the first
locking part(s) from a remote position. It may also be present in
the case that the first locking part(s) is/are activated by means
of a hydraulic or a pump system, in which case the first locking
part(s) may be moved to the release position in case of a failure
in the activating system, e.g. due to a leaking or bursting oil
pipe. Furthermore, if the first locking part(s) is/are in the form
of tapered pins, the risk that they are moved to the release
position during a failure as described above is increased. Fixating
the first locking part(s) in the locking position prevents these
situations and eliminates the risk that the hub accidentally starts
rotating during the maintenance operation.
The locking arrangement of the invention may advantageously form
part of a wind turbine further comprising a tower construction, a
nacelle, and a rotor carrying a set of turbine blades.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in further detail with
reference to the accompanying drawings in which
FIG. 1 is a perspective view of a part of a wind turbine having
base frame and a hub with a locking arrangement according to an
embodiment of the invention arranged thereon,
FIG. 2 is a perspective view of the hub of the wind turbine of FIG.
1,
FIG. 3 is a cross sectional view of the locking arrangement
arranged on the wind turbine of FIG. 1, the locking arrangement
being in a release position, and
FIG. 4 is a cross sectional view of the locking arrangement
arranged on the wind turbine of FIG. 1, the locking arrangement
being in a locking position.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of parts of a wind turbine. For the
sake of clarity, some parts, such as the tower construction and the
nacelle, have been omitted, thereby revealing parts which are
relevant for the purpose of describing the present invention.
FIG. 1 shows a hub 1 having three blade flange parts 2, each being
adapted to have a turbine blade attached thereto. FIG. 1 further
shows a main shaft 3 attached to the hub 1 via flange 4, and the
main shaft 3 therefore rotates along when the hub 1 rotates. The
main shaft 3 is further connected to a gear arrangement (not
shown). Finally, FIG. 1 shows part of a base frame 5.
Two first locking parts 6, one of which is visible, are arranged at
opposite positioned, i.e. angularly spaced with 180.degree. between
them. The first locking parts 6 are in the form of pins which are
movable in a substantially radial direction, i.e. substantially
perpendicularly to a direction defined by the rotational axis of
the hub 1 or a direction defined by a longitudinal direction of the
main shaft 3. This will be described in further detail below with
reference to FIGS. 3 and 4.
The hub 1 is provided with a flange part 7 having twelve openings
8, five of which are visible, formed therein. The openings 8 are
arranged substantially equidistantly along the perimeter defined by
the flange part 7, i.e. with an angular spacing of approximately
30.degree. between neighbouring openings 8. The openings 8
constitute second locking parts. In the embodiment shown in FIG. 1
the flange part 7 forms an integral part of the hub 1.
When the relative position of the hub 1 and the base frame 5 is
such that an openings 8 is arranged adjacent to each of the first
locking parts 6, the pins of the first locking parts 6 can be moved
along a substantially radial direction towards the flange part 7,
and the pins are received in the openings 8. Thereby the pins and
the openings 8 in combination prevent the hub 1 from performing
rotational movements relative to the base frame 5, i.e. the hub 1
is locked.
Due to the large number of openings 8 formed in the flange part 7,
it is possible to lock the hub 1 and the base frame 5 together at
relative positions which are angularly spaced apart at
approximately 30.degree..
FIG. 2 is a perspective view of the hub 1 of FIG. 1, seen from a
different angle. The flange part 7 and six of the openings 8 can
clearly be seen.
FIGS. 3 and 4 are cross sectional views of part of the locking
arrangement arranged on the wind turbine of FIG. 1. One of the
first locking parts 6 can be seen. In FIG. 3 the first locking part
6 is in a release position and in FIG. 4 the first locking part 6
is in a locking position.
The first locking part 6 comprises a pin 9 which is connected to a
pump cylinder 10. When the pump cylinder 10 is activated, the pin 9
is pushed in a direction towards the flange part 7. The pin 9 has a
tapered shape. Therefore the diameter of the outermost part of the
pin 6 is smaller than the diameter of the opening 8 at the position
which is closest to the base frame 5. This can be clearly seen in
FIG. 3. This allows the pin 9 to be moved into the opening 8, even
if the pin 9 and the opening 8 are not perfectly aligned. In FIG. 3
the relative position of the hub 1 and the base frame 5 is such
that the pin 9 and the opening 8 are perfectly aligned, and it is
therefore possible to move pin 9 into the opening 8, thereby moving
the first locking part 6 to the locking position.
FIG. 4 shows the first locking part 6 in the locking position. It
can be seen that the pump cylinder 10 has been activated to push
the pin 9 towards the opening 8 by means of a piston. The opening 8
has a tapered shape which matches the tapered shape of the pin 9.
This allows the pin 9 to fit snugly into the opening 8 when the pin
9 has been moved completely to the locking position, as shown in
FIG. 4.
In FIGS. 3 and 4 it can also be seen that a space is defined
between a wall part of the base frame 5 and a plate 11 used for
mounting the first locking part 6 on the base frame 5. This allows
maintenance personnel to visually inspect whether or not the first
locking part 6 has been moved to the locking position, thereby
rendering it safe to initiate the maintenance operation.
Furthermore, it is possible to mechanically lock the first locking
part 6 in the locking position by positioning a block or the like
in the space, thereby preventing that the pin 9 is moved back to
the release position shown in FIG. 3. This prevents that the first
locking part 6 is accidentally moved to the release position during
maintenance. This is in particular advantageous in the case that it
is possible to activate the first locking part 6 remotely.
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